Recent allegations that a 35-year-old pastor sexually abused at least 26 teenage girls in his youth ministry group have refueled the debate over the manipulative tactics of sex offenders in the clergy.

On Tuesday, four of the alleged victims — masked and covered in black — spoke out against a pastor at their church in Incheon, claiming he "groomed" them into accommodating his sexual demands for years in their teens.

"Every time I said no, he told me he loved me, saying it was the first time he felt this way about someone," one of the victims said at a press conference held at a Christian meeting hall in Yeonji-dong, Seoul. "I trusted the pastor, so I never thought he could lie in God's name."

The pastor, surnamed Kim, approached young female students in the youth ministry of his church, buying them treats and gently counseling them on family issues. As the girls started to trust him more, Kim started making sexual comments or touching them. He convinced the girls they were in loving relationships that would eventually end in marriage. Gradually, he got them to have sex with him regularly, telling them he wanted to "purify" bad memories of being raped by his uncle.

"It was hard for the victims to even register their situation as sexual abuse while they were stuck in the continuous cycle of psychological brainwashing and rape," Chae Su-ji, head of the Christian Counseling Center for Violence Against Women, told The Korea Times, Wednesday.

"As the relationship deepens and the young person is forced to keep secrets, she is increasingly isolated from others, making it easier for the pastor to psychologically control her."

Kim, son of the head pastor, carried on this tactic with multiple girls at a time. His behavior was noticed by the church leadership, but went unpunished for the last 10 years.

His tactics are echoed in similar cases that have been pulled out of the shadows by the #MeToo movement earlier this year, like the notorious Lee Jae-rock, a senior pastor at the 140,000-strong Manmin Central Church now on trial for raping seven female followers.

Perpetrators tend to target the most vulnerable, using the victim's faith.

"The perpetrators approach the most vulnerable, or those who are alone and don't have friends or parent figures they can openly talk to," Chae said. "They also use the fact that young Christian girls, especially those with absent or abusive fathers, see a pastor as a second father whom they idealize and want validation from."

The Christian center has received over 400 consultations — triple the annual average — since January, when the #MeToo movement caught on in the country.

Over 680 religious leaders were apprehended for sexual abuse from 2010 to 2016, according to police records, but many more crimes went unreported, experts say.

Proper punishment is another issue. When a female pastor whom one of the victims confided in recently called out Kim's actions, the victims were threatened, bribed, and even accused of cult activities, the victims say.